1. Field of the Invention
The field of the invention is electronic controllers, including programmable controllers, numerical controls and motion controllers.
2. Description of the Background Art
A programmable controller for controlling industrial machines and processes typically has a PC system processor and a group of input and output (I/O) interface modules mounted in a chassis. A slot at the left end can accommodate a programmable controller processor module. The I/O modules are mounted in the slots of the chassis not occupied by the programmable controller processor.
In early programmable controllers, I/O modules were designed to be wired to discrete output devices such as solenoids, relays and motor starters or to discrete input devices such as limit switches, photoelectric sensors and proximity sensors. Later, more complex I/O modules were developed to control analog input and output devices, and to sense and control variables such as position, velocity or temperature. More recently, the assignee of the present invention has introduced a single-axis motion control I/O module which may be situated in a programmable controller chassis with a programmable controller processor, and which communicates data with the programmable controller processor during an I/O scan of modules in the rack. Unlike prior I/O modules, however, these motion control I/O modules receive motion control programs, compiled from a high-level language, through a programming port on the front of the I/O module. The programs executed by the motion control I/O modules, may in some instance be longer, more complex and more sophisticated than the control program executed by programmable controller processor in the same equipment rack. The programmable controller processor, however, is useful in transferring certain motion commands and parameter data to the motion control I/O module for execution in conjunction with the high-level language program.
There remains, however, a problem in programming these motion control I/O modules, in that in a large facility, they may be distributed in chassis at many remote locations. The only access for programming the single-axis modules was through direct connection to a port on the front of the module. This requires that technical personnel walk from location to location, between programming tasks, moving the programming terminal to the next individual location and connecting it to the next module. It would therefore be desirable for the motion control I/O modules to be programmed more efficiently.
In recent years, programmable controller processors have been connected with programmable processors in other equipment racks through peer-to-peer networks as disclosed in Roach et al., U.S. Pat. No. 4,747,100, issued May 24, 1988. A rack-based programmable controller processor suitable for peer-to-peer communications is disclosed in Rohn et al. U.S. Pat. No. 4,742,443, issued May 3, 1988. A programming terminal may be connected to these networks to download programs to programmable controller system processors when these processors are placed in a PROGRAM mode. There has not been, however, a suitable method to download programming files through the programmable controller system processor to I/O modules.